Flexible cover plate, display module and display device

ABSTRACT

A flexible cover plate is described that includes a base layer, a hard coating layer, on the base layer and a cover layer on a side of the hard coating layer away from the base layer. The cover layer is made of a linear organic polymer having a hydrogen bond crosslink network.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon and claims priority to Chinese PatentApplication No. 201911128463.5, filed on Nov. 18, 2019, where the entirecontents thereof are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to the technical field of displays and,in particular, to a flexible cover plate, a display module, and adisplay device.

BACKGROUND

With the development of various display techniques, the requirements forvarious performance of a screen are increasing due to wide use ofdisplay devices. As flexible screens have bendable and rollingcharacteristics, it is possible to bend, fold, or roll the displaydevice, so as to bring convenience of carrying and using the displaydevice. Wearable display devices with flexible display panels arepopular, show great potential in entertainment and other fields, andthus have been listed into the main competitive market in the industry.

SUMMARY

In an aspect of the present disclosure, an embodiment of this disclosureprovides a flexible cover plate that includes a base layer, a hardcoating layer, and a cover layer. The hard coating layer is arranged onthe base layer. The cover layer is laminated on a side of the hardcoating layer away from the base layer. The cover layer is made of alinear organic polymer having a hydrogen bond crosslink network.

According to one embodiment of the present disclosure, the cover layeris made of an ether-thiourea linear polymer.

According to one embodiment of the present disclosure, a thickness ofthe cover layer is 5-20 μm.

According to one embodiment of the present disclosure, the cover layeris a single-layer film structure, or the cover layer is a multi-layerfilm structure in which at least two layers of films are laminated.

According to one embodiment of the present disclosure, the flexiblecover plate comprises a display area and a non-display area surroundingthe display area, and the cover layer at least covers the display area.

According to one embodiment of the present disclosure, the base layer ismade of one or more materials selected from polyimide, polyethylene andpolymethyl methacrylate, or the base layer is made of a flexible glassmaterial.

According to one embodiment of the present disclosure, the hard coatinglayer is made of an acrylate material.

According to one embodiment of the present disclosure, a thickness ofthe flexible cover plate is not more than 200 μm.

In another aspect, an embodiment of the present disclosure provides adisplay module, which includes the flexible cover plate mentioned above.

In another aspect, an embodiment of the present disclosure provides adisplay device, which includes the display module mentioned above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural view of a flexible cover plate providedby an embodiment of the present disclosure.

DETAILED DESCRIPTION

In order to further explain the technical means adopted to achieve theintended purpose and its effects, a flexible cover plate, a displaymodule, and a display device are proposed according to the presentdisclosure, and specific implementations, structures, characteristics,and effects thereof will be described in detail below with reference tothe drawing and various embodiments.

A flexible cover plate generally serves as a protective structure of thesurface layer of the flexible display module. Currently, the flexiblecover plate is usually made of polymer materials such as PI and PET,which have poor strength and impact resistance, so that display failureof a display screen occurs under the impact of heavy objects, forexample a ball or a pen falls down, because cracks are generated on afilm layer at a position where a pen tip or a ball body falls down, andabnormity such as pits and black spots are presented at the positionwhere the pen tip or the ball body falls down.

An embodiment of the present disclosure provides a flexible cover plate,a display module, and a display device, generally to solve such problemthat the flexible cover plate has poor impact resistance and easilyaffects display of the display module in the prior art.

As shown in FIG. 1 , a flexible cover plate as proposed in the presentdisclosure includes a base layer 1, a hard coating layer 2, and a coverlayer 3.

The hard coating layer 2 is arranged on the base layer 1.

The cover layer 3 is provided on a side of the hard coating layer awayfrom the base layer, where the cover layer is made of a linear organicpolymer having a hydrogen bond crosslink network.

For example, the flexible cover plate plays a supporting role as asurface structure of the display module and also is required to protecta polarizer, an elastic support layer, and a display device under theflexible cover plate from being damaged, so that the flexible coverplate is allowed to have sufficient strength and impact resistance. Theflexible cover plate proposed in this embodiment includes three layersstructures laminated. A base layer 1 is positioned on the bottom of theflexible cover plate as the flexible base. The material of the baselayer 1 may be one or more of polyimide, polyethylene, and polymethylmethacrylate. The base layer 1 made of polymer organic materials canmeet the requirements for bending or rolling the flexible cover platebecause of its good bending performance. Alternatively, the material ofthe base layer 1 may also be made of flexible glasses having rigidcharacteristics, so that the flexible cover layer has some strength andsome bending performance, that is to say, the base layer 1 made of theflexible glass material can have better bending performance andstrength. The hard coating layer 2 is laminated on the base layer 1 toform a film layer by a coating process, and the thickness of the hardcoating layer 2 may be 5-15 such as 5 μm, 8 μm, 10 μm, 12 μm, 14 μm, andthe like. In this embodiment, an advantage having flexibility andrigidity can be achieved by arranging the hard coating layer 2 on thesurface of the base layer 1 of the flexible glass. For example, the hardcoating layer 2 may be made of acrylate materials, and may be coated onthe surface of the base layer 1. Since the acrylate material may becross-linked and cured under ultraviolet (UV) radiation or by heating,the cured products may have rigidity and flexibility, so that theacrylate material is adapted to be used as the hard coating layer 2.

The flexible cover plate that is formed by laminating the base layer 1and the hard coating layer 2 has a certain rigidity and flexibility, andthereby having a good bending performance. A display failure is causedunder the impact of heavy objects, for example a ball or a pen fallsdown, because cracks are generated on a film layer at a position where apen tip or a ball body falls down, and abnormities, such as pits andblack spots, are presented at the position where the pen tip or the ballbody falls down, so that a normal display of the display module isaffected. In order to further solve the problem of poor impactresistance of the flexible cover plate, in this embodiment, the hardcoating layer 2 is provided with a cover layer 3 which is made of alinear organic polymer and in which a hydrogen bond crosslink network isformed. When low molecular weight organic polymers are cross-linked bydense hydrogen bonds, although they possess extremely slow diffusionkinetics, materials with high mechanical strength are easy to berepaired and can be produced. A high mechanical strength and stablerepair ability can be realized, and furthermore the impact resistance ofthe flexible cover plate can be improved through interaction of thehydrogen bonds among various monomers in a low molecular weight organicpolymer matrix. The above-mentioned stable repairability depends on anextrinsic or intrinsic repair behavior of a linear organic polymer, andan external healing ability depends on small capsules or blood vesselnetwork which are finely dispersed inside thereof. The polymer materialsare embedded under the monomer broken when being mixed and an initiator,and can be connected with the breakage to form a new polymer chain, sothat self-repair function can be realized. Such repairable polymermaterials are normally soft and deformable to meet the bendingperformance requirements of flexible cover plate. Through such designthat the hydrogen bonds are interacted with one another and cross-linkedwith dynamic covalent bonds, the polymer materials can be self-repairedafter the temperature or the pressure is increased, for example, thevalues of the temperature or the pressure may be determined according tothe actual situations and the types of the linear organic polymers, thatis, the damaged portion of the flexible cover plate can be repairedthrough operation of rising the temperature or the pressure locally atthe fixed point thereof so as to improve the yield of the products whenthe surface of the flexible cover plate is damaged at a stage frommanufacturing the products to transporting the products out of thefactory.

The impact resistance of the flexible cover plate can be improved viathe hydrogen bond crosslink network inside the materials of the coverlayer 3, since the thickness of the cover layer 3 when beingspecifically arranged may be set to about 5-20 μm, such as 6 μm, 8 μm,10 μm, 12 μm, 14 μm, 15 μm, 17 μm, 18 μm, etc., it is not necessary toincrease the overall thickness of the flexible cover plate to improvethe strength and impact resistance of the flexible cover plate, so thatit is beneficial to design the flexible cover plate thinner and notaffect the bending performance of the flexible cover plate when thestrength and impact resistance are increased.

An embodiment of the present disclosure provides a flexible cover plate,which is formed by laminating three layers structures. A base layer ispositioned on the bottom of the flexible cover plate as the flexiblebase, and a hard coating layer is arranged on the upper side of the baselayer to achieve the effect having flexibility and rigidity. In order toenhance the impact resistance of the flexible cover plate, a cover layeris arranged on the surface of the hard coating layer and is made of alinear organic polymer having a hydrogen bond crosslink network. A highmechanical strength and stable repair ability can be realized, andfurthermore, the impact resistance of the flexible cover plate can beimproved without increasing the thickness of the flexible cover plate toensure the bending performance thereof through interaction of thehydrogen bonds among various monomers in a low molecular weight organicpolymer matrix. The portion locally damaged on the surface of the coverlayer can be repaired through operation of rising the temperature or thepressure locally so as to improve the yield of the products before theflexible cover plates are transported out of the factory.

The cover layer 3 is made of the linear organic polymer, in which thehydrogen bond crosslink network is formed. For example, the cover layer3 may be made of the ether-thiourea linear polymer, which is one of thelinear organic polymers, in which the hydrogen bond network can beformed. A zigzag hydrogen bond array is abnormally formed by usingthiourea monomer, which cannot cause unfavorable crystallization andallows the presentation of a thiourea unit with the hydrogen bond. Themonomer in the organic polymer matrix can activate exchange of thehydrogen bonds. The high mechanical strength and stable repaircapability are achieved by the dense crosslink of the hydrogen bonds.For example, the manufacturing method of the cover layer 3 is coatingthe ether-thiourea linear polymer material on the hard coating layer 2to form a thin film with a preset thickness. The Ether-thiourea linearpolymer, for example has following forms:

{circle around (1)} an ether-thiourea linear polymer with diethyleneglycol (TUEG 2), triethylene glycol (TUEG 3) and tetraethylene glycol(TUEG 4) as a space group, the chemical formula is as follows:

{circle around (2)} an ether-urea linear polymer with triethylene glycol(LEG 3) as a space group, the chemical formula is as follows:

In order to improve the impact resistance of the flexible cover plate,the main method adopted includes: increasing the thickness of thepolymer layer, or adopting a film structure composed of two or morepolymer layers, and connecting adjacent polymer layers by coating anoptical adhesive to form an integrated structure. Through use of thesemethods, the improvement of the impact resistance of the flexible coverplate is limited, but the overall thickness of the flexible cover platecan be increased greatly and thereby affecting the bending performanceof the flexible cover plate. The flexible cover plate proposed in thisembodiment includes the cover layer 3 located at the top layer. Thecover layer is made of the linear organic polymer material, in which themonomers are cross-linked by the dense hydrogen bonds, so as to obtain ahigher strength and impact resistance, and the material itself hasbetter impact resistance, so that there is no need to increase thethickness in order to enhance the strength and impact resistance. Thecover layer 3 in the specific use is a thin film layer covering thesurface of the hard coating layer 2. The thickness of the cover layer 3may be 5-20 μm. Now, the overall thickness of the flexible cover plateis more than 200 μm, so that the thickness of the cover layer 3 issmaller relative to the overall thickness of the flexible cover plate,and the bending performance of the flexible cover plate cannot beaffected. Furthermore, the cover layer may be a single-layer filmstructure, or a multi-layer film structure formed by at least two filmslaminated.

The flexible cover includes a display area and a non-display areasurrounding the display area. After the flexible cover is applied to thedisplay module, a display device is correspondingly arranged on thelower side of the display area of the flexible cover, to realize thedisplay function. This embodiment is not limited to the specificconfiguration of the display device layer, for example, the displaydevice may include an OLED layer, a touch panel, a polarizer and otherstructures. In order to avoid affecting the normal display effect of thedisplay module and protect the display device layer from being damaged,a coverage area of the cover layer 3 may be set to at least cover thedisplay area, or may also cover the whole area of the flexible coverplate.

For example, the base layer 1 may be made of various materials, such aspolyimide, polyethylene and polymethyl methacrylate. The base layer 1made of the polymer organic materials has better bending performance andcan meet the requirements for bending and rolling the flexible coverplate, alternatively the material of the base layer 1 may also be madeof a flexible glass, which has the rigidity characteristics of glassmaterials to make it have a certain strength, and also has a certainbending performance, so that the base layer 1 made of the flexible glasscan have better bending performance and a certain rigidity.

For example, an effect having flexibility and rigidity can be achievedby arranging the hard coating layer 2 on the base layer 1. The hardcoating layer 2 may be made of an acrylate material, for example, may becoated on the surface of the base layer 1. Since the acrylate materialmay be cross-linked and cured under ultraviolet (UV) radiation or byheating, the cured products may have rigidity and flexibility, so thatthe acrylate material is adapted to be used as the hard coating layer 2,which however is not limited thereto.

In order not to affect the bending performance of the flexible coverplate, the overall thickness of the flexible cover plate may be reducedas much as possible under the condition of that its strength and impactresistance can meet the requirements. The base layer 1 used as theflexible base of the cover plate plays a supporting role, and has athickness that is much greater than that of the hard coating layer 2 andthe cover layer 3. The thickness of base layer 1 may be 50-150 μm, suchas 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm,etc. The thickness of cover layer 3 may be 5-20 μm, and the thickness ofhard coating layer 2 may be equal to or slightly smaller than that ofthe cover layer 3. The thickness of the hard coating layer 2 may beabout 5-15 μm, and the overall thickness of the flexible cover plate maybe made to be not more than 200 μm, so as to have a better bendingperformance and thus can be applied to the flexible module.

The present disclosure provides a display module including the flexiblecover plate according to the present disclosure.

For example, the display module may include a base substrate disposed atthe bottom and a display device layer disposed between the basesubstrate and the flexible cover plate. The arrangement of the flexiblecover plate can bring a better support and reliable protection for thedisplay device layer, so as to avoid the display device layer from beingdamaged.

An embodiment of the present disclosure provides a display module. Byusing the flexible cover plate composed of a base layer 1, a hardcoating layer 2, and a cover layer 3, the surface strength and theimpact resistance of the display module can be improved, therebyimproving the display effect of the display module, meeting thelightweight design requirements of the display module, and ensuring abetter bending performance of the display module.

The present disclosure provides a display device including the displaymodule according to the present disclosure.

For example, the display device may be an electronic device, such as amobile phone, a tablet, a computer and the like, with a displayfunction. The above display module is used in the display device torealize the display function.

An embodiment of the present disclosure provides a display device, inwhich a thin and light display module having strong impact resistance isused to improve the display effect of electronic equipment, andfacilitate reducing the overall thickness of the display device andimprove the bending performance of the display device.

It should be noted that orientation or position relationship asindicated by the terms “upper” and “lower” is orientation or positionrelationship as shown in the drawings according to the description ofthis specification, only for the convenience of describing thisdisclosure and simplifying the description, but not for indicating orsuggesting that the referred device or element must have a specificorientation, constructed and operated in a specific orientation, so thatit cannot be understood as limiting the present disclosure. The terms“connect”, “install” and “fix” should be understood in a broader sense,for example, “connect” may be a fixed connection, a detachableconnection or an integral connection, or being connected directly orbeing connected indirectly through an intermediate medium. For thoseskilled in the art, the specific meanings of the above terms in thisdisclosure should be understood according to specific situations.

According to the description of this specification, the description ofthe terms “an embodiment”, “some embodiments”, “specific embodiments”,etc. is intended to mean that specific features, structures, materials,or characteristics described in connection with this embodiment orexample are included in at least one embodiment or example of thepresent disclosure. In this specification, the illustrations of theabove terms do not necessarily refer to the same embodiments orexamples. Furthermore, the specific features, structures, materials orcharacteristics may be combined in any one or more embodiments orexamples in a suitable manner.

The above described are merely the specific embodiments of the presentdisclosure, but the present disclosure is not limited thereto. Anyvariation or substitution can be easily envisaged by those skilled inthe art and can be embraced within the present disclosure. It isintended that the scope of the invention only be limited by the appendedclaims.

What is claimed is:
 1. A flexible cover plate comprising a display areaand a non-display area surrounding the display area, and furthercomprising: a base layer; a hard coating layer on the base layer; and acover layer on a side of the hard coating layer away from the baselayer; wherein the cover layer is made of a linear organic polymerhaving a hydrogen bond crosslink network, a thickness of the cover layeris 5 μm, the cover layer is a multi-layer film structure in which atleast two layers of films are laminated, and the cover layer at leastcovers the display area.
 2. The flexible cover plate according to claim1, wherein the cover layer is made of an ether-thiourea linear polymer.3. The flexible cover plate according to claim 1, wherein the base layeris made of at least one of: polyimide, polyethylene, and polymethylmethacrylate, or the base layer is made of a flexible glass material. 4.The flexible cover plate according to claim 1, wherein the hard coatinglayer is made of an acrylate material.
 5. The flexible cover plateaccording to claim 1, wherein a thickness of the flexible cover plate isnot more than 200 μm.
 6. A display module comprising a display area anda non-display area surrounding the display area, and further comprisinga flexible cover plate, wherein the flexible cover plate comprises: abase layer; a hard coating layer on the base layer; and a cover layer ona side of the hard coating layer away from the base layer; wherein thecover layer is made of a linear organic polymer having a hydrogen bondcrosslink network, a thickness of the cover layer is 5 μm, the coverlayer is a multi-layer film structure in which at least two layers offilms are laminated, and the cover layer at least covers the displayarea.
 7. The display module according to claim 6, wherein the coverlayer is made of an ether-thiourea linear polymer.
 8. The display moduleaccording to claim 6, wherein the base layer is made of at least onematerial selected from polyimide, polyethylene, and polymethylmethacrylate, or the base layer is made of a flexible glass material. 9.The display module according to claim 6, wherein the hard coating layeris made of an acrylate material.
 10. The display module according toclaim 6, wherein a thickness of the display module is not more than 200μm.
 11. A display device, comprising: a display module comprising adisplay area and a non-display area surrounding the display area, andfurther comprising a flexible cover plate, the flexible cover platecomprising: a base layer; a hard coating layer on the base layer; and acover layer on a side of the hard coating layer away from the baselayer; wherein the cover layer is made of a linear organic polymerhaving a hydrogen bond crosslink network, a thickness of the cover layeris 5 μm, the cover layer is a multi-layer film structure in which atleast two layers of films are laminated, and the cover layer at leastcovers the display area.
 12. The display device of claim 11, wherein thecover layer is made of an ether-thiourea linear polymer.
 13. The displaydevice of claim 11, wherein the base layer is made of at least one of:polyimide, polyethylene, and polymethyl methacrylate, or the base layeris made of a flexible glass material.
 14. He display device of claim 11,wherein the hard coating layer is made of an acrylate material.
 15. Thedisplay device of claim 11, wherein a thickness of the flexible coverplate is not more than 200 μm.